Select all targets of an object's Boolean modifiers
Here's a script that adds an operator to do that in the &quot;Select&quot; menu.
I added 3 checkboxes to specifiy if you want to include hidden (eye icon), disabled (monitor icon) or unselectable objects, since by default they can't be selected if they are in either of these states.
The operator selects everything by default, hidden, selectable or not.
import bpy


class SelectBooleansOperator(bpy.types.Operator):
    bl_label = &quot;Select Linked Booleans&quot;
    bl_idname = &quot;object.select_linked_booleans&quot;
    bl_options = {'REGISTER', 'UNDO'}
    
    extend: bpy.props.BoolProperty(
        name=&quot;Extend&quot;,
        default=False,
        )
        
    select_hidden: bpy.props.BoolProperty(
        name=&quot;Select Hidden&quot;,
        default=True,
        )
        
    select_disabled: bpy.props.BoolProperty(
        name=&quot;Select Disabled&quot;,
        default=True,
        )
    
    select_unselectable: bpy.props.BoolProperty(
        name=&quot;Select Unselectable&quot;,
        default=True,
        )
    
    @classmethod
    def poll(cls, context):
        return context.active_object and context.active_object.type == 'MESH'

    def execute(self, context):
        layout = self.layout
        
        mods = context.active_object.modifiers
        
        for mod in mods:
            if mod.type != 'BOOLEAN':
                continue
            
            obj = mod.object
            
            # Logic from https://blenderartists.org/t/blender-2-8-python-hide-unhide-objects/1141228/2
            
            if (not obj.hide_viewport and not obj.visible_get()) and self.select_hidden: 
                # Hidden with the eye icon
                obj.hide_set(False)
                
            if obj.hide_viewport:
                obj.hide_viewport = False #  Toggle to test visibility
            
                if obj.visible_get() and self.select_disabled:
                    # Hidden with the monitor icon
                    obj.hide_viewport = False              
                elif self.select_disabled and self.select_hidden:
                    # Hidden both ways
                    obj.hide_viewport = False
                    obj.hide_set(False)
                else:
                    obj.hide_viewport = True #  Toggle back          
                        
            if obj.hide_select and self.select_unselectable:
                obj.hide_select = False
            
            mod.object.select_set(True)
            
        context.active_object.select_set(self.extend)
        
        return {'FINISHED'}

def draw_item(self, context):
    self.layout.operator(SelectBooleansOperator.bl_idname)


def register():
    bpy.utils.register_class(SelectBooleansOperator)
    bpy.types.VIEW3D_MT_select_object.append(draw_item)


def unregister():
    bpy.utils.unregister_class(SelectBooleansOperator)
    bpy.types.VIEW3D_MT_select_object.remove(draw_item)


if __name__ == &quot;__main__&quot;:
    register()

How to use :
How to run a script

Note that you would have to re-run the script every time you close and open Blender. If you want it to be persistent, make it into an add-on.
You can also add a shortcut to the operator by right clicking it in the menu.